Variability of CVP and Fluid Overload are Associated with Sepsis-associated Acute Kidney Injury: a case-control study

Background: The relationship between central venous pressure (CVP) and sepsis-associated acute kidney injury is not extensively explored. The study aimed to investigate the association of CVP and new-onset SAKI.Methods: Septic patients with new-onset AKI (SAKI) were identified from the Medical Information Mart for Intensive Care (MIMIC)-III database. Propensity score (PS) was used to account for the baseline differences between SAKI and non-SAKIs. In order to estimate association between CVP variability and AKI, we applied the generalize estimate equation (GEE) to adjust for potential confounding such as cumulative fluid balance and in-ICU medication usage. Results: A total of 916 septic patients with new-onset AKI were enrolled in the study, including 458 in the SAKI group and 458 in non-SAKI group. After PS matching, baseline factors such as SOFA, SAOSII, APSIII and LODS score, as well as baseline diseases including hypertension, diabetes, liver and renal disease were balanced between SAKIs and non-SAKIs. SAKI groups showed higher CVP variation (SAKI vs.non-SAKI:0.83 vs.0.68, p=0.03) and accumulative fluid balance (SAKI vs. non-SAKI: Day 1:3449.8 vs.2930.3; Day 2:4801.1 vs. 3916.6; Day 3: 6018.5 vs.5005.8, p=0.007). GEE was further used to estimate the association between CVP variation and SAKI. The model showed that, increased CVP variation (OR=1.14 ,95%CI 1.01-1.28, p=0.03), higher fluid accumulation (OR=1.02 95%CI 1.00-1.05, p=0.04) were associated with increased risk of SAKI. Conclusions: We found that variability of CVP and higher fluid accumulation were associated with higher risk of new-onset SAKI in septic patients in this study. The results need to be verified in further prospective trials.